Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources.
Uplink packet transmissions typically operate based on a request-grant mechanism. For example, a subordinate entity (e.g., UE) intending to transmit an uplink packet to a scheduling entity (e.g., base station) may send a request for transmission resources to the scheduling entity. In response, the scheduling entity may provide a grant of resources to the subordinate entity based on the request. The subordinate entity may then transmit the uplink packet based on the grant. However, such request-grant mechanism may increase packet latency as a number of signals/messages need to be exchanged before the subordinate entity is granted the resources to transmit the uplink packet.
In applications that require a low packet latency, delay may be reduced by forgoing the request-grant mechanism and allowing subordinate entities to transmit in an unscheduled mode in a distributed manner without waiting for a grant. However, such a distributed transmission mechanism is susceptible to collisions since multiple subordinate entities may transmit over the same resource. Accordingly, there is a need for a mechanism that limits transmission collisions without incurring the typical overhead and delay associated with the subordinate entities communicating with the scheduling entity.
As the demand for mobile broadband access continues to increase, research and development continue to advance wireless communication technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.